Fix issues with Arm's use of embedded constant pools

src/arm64/assembler-arm64.cc

Index: src/arm64/assembler-arm64.cc
diff --git a/src/arm64/assembler-arm64.cc b/src/arm64/assembler-arm64.cc
index 5445fe1a1b19a9bd8f01a4e9afb80a32f8b3493a..46a2b8e86e4210692f0f79b5d47f031fd0026969 100644
--- a/src/arm64/assembler-arm64.cc
+++ b/src/arm64/assembler-arm64.cc
@@ -596,6 +596,14 @@ void Assembler::Align(int m) {
 }
 
 
+void Assembler::DataAlign(int m) {
+  DCHECK(m >= 2 && base::bits::IsPowerOfTwo32(m));
+  while ((pc_offset() & (m - 1)) != 0) {
+    db(0);
+  }
+}
+
+
 void Assembler::CheckLabelLinkChain(Label const * label) {
 #ifdef DEBUG
   if (label->is_linked()) {